cfg80211/nl80211: add API for MAC address ACLs

Add API to enable drivers to implement MAC address based
access control in AP/P2P GO mode. Capable drivers advertise
this capability by setting the maximum number of MAC
addresses in such a list in wiphy->max_acl_mac_addrs.

An initial ACL may be given to the NL80211_CMD_START_AP
command and/or changed later with NL80211_CMD_SET_MAC_ACL.

Black- and whitelists are supported, but not simultaneously.

Signed-off-by: Vasanthakumar Thiagarajan <vthiagar@qca.qualcomm.com>
[rewrite commit log, many cleanups]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Git-commit: 77765eaf5cfb6b8dd98ec8b54b411d74ff6095f1
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
CRs-fixed: 487410
Change-Id: I9593b887941be5efa5e96546ad92cd6c6bf8fb87
[duttus@codeaurora.org: resolved 3.4 backport issues]
Signed-off-by: Sunil Dutt <duttus@codeaurora.org>
diff --git a/include/linux/nl80211.h b/include/linux/nl80211.h
index f551e75..6d7d178 100644
--- a/include/linux/nl80211.h
+++ b/include/linux/nl80211.h
@@ -3069,4 +3069,32 @@
 	NL80211_PROBE_RESP_OFFLOAD_SUPPORT_80211U =	1<<3,
 };
 
+/**
+ * enum nl80211_connect_failed_reason - connection request failed reasons
+ * @NL80211_CONN_FAIL_MAX_CLIENTS: Maximum number of clients that can be
+ *  handled by the AP is reached.
+ * @NL80211_CONN_FAIL_BLOCKED_CLIENT: Connection request is rejected due to ACL.
+ */
+enum nl80211_connect_failed_reason {
+	NL80211_CONN_FAIL_MAX_CLIENTS,
+	NL80211_CONN_FAIL_BLOCKED_CLIENT,
+};
+
+/**
+ * enum nl80211_acl_policy - access control policy
+ *
+ * Access control policy is applied on a MAC list set by
+ * %NL80211_CMD_START_AP and %NL80211_CMD_SET_MAC_ACL, to
+ * be used with %NL80211_ATTR_ACL_POLICY.
+ *
+ * @NL80211_ACL_POLICY_ACCEPT_UNLESS_LISTED: Deny stations which are
+ *   listed in ACL, i.e. allow all the stations which are not listed
+ *  in ACL to authenticate.
+ * @NL80211_ACL_POLICY_DENY_UNLESS_LISTED: Allow the stations which are listed
+ *    in ACL, i.e. deny all the stations which are not listed in ACL.
+ */
+enum nl80211_acl_policy {
+	NL80211_ACL_POLICY_ACCEPT_UNLESS_LISTED,
+	NL80211_ACL_POLICY_DENY_UNLESS_LISTED,
+};
 #endif /* __LINUX_NL80211_H */
diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index dc29eb9..fb2b57a 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -416,6 +416,26 @@
 	size_t probe_resp_len;
 };
 
+struct mac_address {
+	u8 addr[ETH_ALEN];
+};
+
+/**
+ * struct cfg80211_acl_data - Access control list data
+ *
+ * @acl_policy: ACL policy to be applied on the station's
+ *	entry specified by mac_addr
+ * @n_acl_entries: Number of MAC address entries passed
+ * @mac_addrs: List of MAC addresses of stations to be used for ACL
+ */
+struct cfg80211_acl_data {
+	enum nl80211_acl_policy acl_policy;
+	int n_acl_entries;
+
+	/* Keep it last */
+	struct mac_address mac_addrs[];
+};
+
 /**
  * struct cfg80211_ap_settings - AP configuration
  *
@@ -432,6 +452,8 @@
  * @privacy: the BSS uses privacy
  * @auth_type: Authentication type (algorithm)
  * @inactivity_timeout: time in seconds to determine station's inactivity.
+ * @acl: ACL configuration used by the drivers which has support for
+ *	MAC address based access control
  */
 struct cfg80211_ap_settings {
 	struct cfg80211_beacon_data beacon;
@@ -444,6 +466,7 @@
 	bool privacy;
 	enum nl80211_auth_type auth_type;
 	int inactivity_timeout;
+	const struct cfg80211_acl_data *acl;
 };
 
 /**
@@ -1559,6 +1582,13 @@
  *	later passes to cfg80211_probe_status().
  *
  * @set_noack_map: Set the NoAck Map for the TIDs.
+ * @set_mac_acl: Sets MAC address control list in AP and P2P GO mode.
+ *	Parameters include ACL policy, an array of MAC address of stations
+ *	and the number of MAC addresses. If there is already a list in driver
+ *	this new list replaces the existing one. Driver has to clear its ACL
+ *	when number of MAC addresses entries is passed as 0. Drivers which
+ *	advertise the support for MAC based ACL have to implement this callback.
+ *
  */
 struct cfg80211_ops {
 	int	(*suspend)(struct wiphy *wiphy, struct cfg80211_wowlan *wow);
@@ -1757,6 +1787,9 @@
 	struct ieee80211_channel *(*get_channel)(struct wiphy *wiphy);
 	int	(*update_ft_ies)(struct wiphy *wiphy, struct net_device *dev,
 				 struct cfg80211_update_ft_ies_params *ftie);
+
+	int (*set_mac_acl)(struct wiphy *wiphy, struct net_device *dev,
+			   const struct cfg80211_acl_data *params);
 };
 
 /*
@@ -1924,10 +1957,6 @@
 	bool beacon_int_infra_match;
 };
 
-struct mac_address {
-	u8 addr[ETH_ALEN];
-};
-
 struct ieee80211_txrx_stypes {
 	u16 tx, rx;
 };
@@ -2068,6 +2097,9 @@
  * @ap_sme_capa: AP SME capabilities, flags from &enum nl80211_ap_sme_features.
  * @ht_capa_mod_mask:  Specify what ht_cap values can be over-ridden.
  *	If null, then none can be over-ridden.
+ *
+ * @max_acl_mac_addrs: Maximum number of MAC addresses that the device
+ *	supports for ACL.
  */
 struct wiphy {
 	/* assign these fields before you register the wiphy */
@@ -2089,6 +2121,8 @@
 	/* Supported interface modes, OR together BIT(NL80211_IFTYPE_...) */
 	u16 interface_modes;
 
+	u16 max_acl_mac_addrs;
+
 	u32 flags, features;
 
 	u32 ap_sme_capa;
diff --git a/net/wireless/core.c b/net/wireless/core.c
index ccdfed8..674c1fa 100644
--- a/net/wireless/core.c
+++ b/net/wireless/core.c
@@ -505,6 +505,11 @@
 			   ETH_ALEN)))
 		return -EINVAL;
 
+	if (WARN_ON(wiphy->max_acl_mac_addrs &&
+		    (!(wiphy->flags & WIPHY_FLAG_HAVE_AP_SME) ||
+		     !rdev->ops->set_mac_acl)))
+		return -EINVAL;
+
 	if (wiphy->addresses)
 		memcpy(wiphy->perm_addr, wiphy->addresses[0].addr, ETH_ALEN);
 
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index e1fa62e..6ed6d3e 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -210,6 +210,8 @@
 	[NL80211_ATTR_USER_REG_HINT_TYPE] = { .type = NLA_U32 },
 	[NL80211_ATTR_SAE_DATA] = { .type = NLA_BINARY, },
 	[NL80211_ATTR_VHT_CAPABILITY] = { .len = NL80211_VHT_CAPABILITY_LEN },
+	[NL80211_ATTR_ACL_POLICY] = {. type = NLA_U32 },
+	[NL80211_ATTR_MAC_ADDRS] = { .type = NLA_NESTED },
 	[NL80211_ATTR_STA_CAPABILITY] = { .type = NLA_U16 },
 	[NL80211_ATTR_STA_EXT_CAPABILITY] = { .type = NLA_BINARY, },
 	[NL80211_ATTR_SPLIT_WIPHY_DUMP] = { .type = NLA_FLAG, },
@@ -1066,6 +1068,11 @@
 			sizeof(*dev->wiphy.ht_capa_mod_mask),
 			dev->wiphy.ht_capa_mod_mask);
 
+	if (dev->wiphy.flags & WIPHY_FLAG_HAVE_AP_SME &&
+	    dev->wiphy.max_acl_mac_addrs)
+		NLA_PUT_U32(msg, NL80211_ATTR_MAC_ACL_MAX,
+			    dev->wiphy.max_acl_mac_addrs);
+
 	return genlmsg_end(msg, hdr);
 
  nla_put_failure:
@@ -2105,6 +2112,97 @@
 	return err;
 }
 
+/* This function returns an error or the number of nested attributes */
+static int validate_acl_mac_addrs(struct nlattr *nl_attr)
+{
+	struct nlattr *attr;
+	int n_entries = 0, tmp;
+
+	nla_for_each_nested(attr, nl_attr, tmp) {
+		if (nla_len(attr) != ETH_ALEN)
+			return -EINVAL;
+
+		n_entries++;
+	}
+
+	return n_entries;
+}
+
+/*
+ * This function parses ACL information and allocates memory for ACL data.
+ * On successful return, the calling function is responsible to free the
+ * ACL buffer returned by this function.
+ */
+static struct cfg80211_acl_data *parse_acl_data(struct wiphy *wiphy,
+						struct genl_info *info)
+{
+	enum nl80211_acl_policy acl_policy;
+	struct nlattr *attr;
+	struct cfg80211_acl_data *acl;
+	int i = 0, n_entries, tmp;
+
+	if (!wiphy->max_acl_mac_addrs)
+		return ERR_PTR(-EOPNOTSUPP);
+
+	if (!info->attrs[NL80211_ATTR_ACL_POLICY])
+		return ERR_PTR(-EINVAL);
+
+	acl_policy = nla_get_u32(info->attrs[NL80211_ATTR_ACL_POLICY]);
+	if (acl_policy != NL80211_ACL_POLICY_ACCEPT_UNLESS_LISTED &&
+	    acl_policy != NL80211_ACL_POLICY_DENY_UNLESS_LISTED)
+		return ERR_PTR(-EINVAL);
+
+	if (!info->attrs[NL80211_ATTR_MAC_ADDRS])
+		return ERR_PTR(-EINVAL);
+
+	n_entries = validate_acl_mac_addrs(info->attrs[NL80211_ATTR_MAC_ADDRS]);
+	if (n_entries < 0)
+		return ERR_PTR(n_entries);
+
+	if (n_entries > wiphy->max_acl_mac_addrs)
+		return ERR_PTR(-ENOTSUPP);
+
+	acl = kzalloc(sizeof(*acl) + (sizeof(struct mac_address) * n_entries),
+		      GFP_KERNEL);
+	if (!acl)
+		return ERR_PTR(-ENOMEM);
+
+	nla_for_each_nested(attr, info->attrs[NL80211_ATTR_MAC_ADDRS], tmp) {
+		memcpy(acl->mac_addrs[i].addr, nla_data(attr), ETH_ALEN);
+		i++;
+	}
+
+	acl->n_acl_entries = n_entries;
+	acl->acl_policy = acl_policy;
+
+	return acl;
+}
+
+static int nl80211_set_mac_acl(struct sk_buff *skb, struct genl_info *info)
+{
+	struct cfg80211_registered_device *rdev = info->user_ptr[0];
+	struct net_device *dev = info->user_ptr[1];
+	struct cfg80211_acl_data *acl;
+	int err;
+
+	if (dev->ieee80211_ptr->iftype != NL80211_IFTYPE_AP &&
+	    dev->ieee80211_ptr->iftype != NL80211_IFTYPE_P2P_GO)
+		return -EOPNOTSUPP;
+
+	if (!dev->ieee80211_ptr->beacon_interval)
+		return -EINVAL;
+
+	acl = parse_acl_data(&rdev->wiphy, info);
+	if (IS_ERR(acl))
+		return PTR_ERR(acl);
+
+	err = rdev->ops->set_mac_acl(&rdev->wiphy, dev, acl);
+
+	kfree(acl);
+
+	return err;
+}
+
 static int nl80211_parse_beacon(struct genl_info *info,
 				struct cfg80211_beacon_data *bcn)
 {
@@ -2251,9 +2349,18 @@
 			info->attrs[NL80211_ATTR_INACTIVITY_TIMEOUT]);
 	}
 
+	if (info->attrs[NL80211_ATTR_ACL_POLICY]) {
+		params.acl = parse_acl_data(&rdev->wiphy, info);
+		if (IS_ERR(params.acl))
+			return PTR_ERR(params.acl);
+	}
+
 	err = rdev->ops->start_ap(&rdev->wiphy, dev, &params);
 	if (!err)
 		wdev->beacon_interval = params.beacon_interval;
+
+	kfree(params.acl);
+
 	return err;
 }
 
@@ -7063,6 +7170,14 @@
 				  NL80211_FLAG_NEED_RTNL,
 	},
 	{
+		.cmd = NL80211_CMD_SET_MAC_ACL,
+		.doit = nl80211_set_mac_acl,
+		.policy = nl80211_policy,
+		.flags = GENL_ADMIN_PERM,
+		.internal_flags = NL80211_FLAG_NEED_NETDEV |
+				  NL80211_FLAG_NEED_RTNL,
+	},
+	{
 		.cmd = NL80211_CMD_UPDATE_FT_IES,
 		.doit = nl80211_update_ft_ies,
 		.policy = nl80211_policy,